Photographic papers



March 17, 1970 I. H. CRAWFORD 7 3,501,298

PHOTOGRAPHIC PAPERS Filed April 8, 1966 BLACK AND WHITE PHOTOGRAPH/C EMULSION TiO POLYETHYLENE PAPER /)/-CLEAR POLYETHYLENE IRVIN H- CRAWFORD ATTORNEYS United States Patent O 3,501,298 PHOTOGRAPHIC PAPERS Irvin H. Crawford, Rochester, N.Y., assignor to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey Filed Apr. 8, 1966, Ser. No. 541,204 Int. Cl. G03c 1/86, 1/76, 3/00 US. Cl. 96-85 4 Claims ABSTRACT OF THE DISCLOSURE Photographic elements have a support comprising a paper base having thereon polyolefin coating which contains titanium dioxide and bis(alkylbenzoxazole) thiophenes.

This invention relates to novel photographic elements. More particularly, this invention relates to black-andwhite photographic papers of improved characteristics.

In its simplest form photographic paper is composed of paper sheet having black-and-white photographic emulsion thereon. This leaves much to be desired in brightness and smoothness, hence, for high quality photographic papers a baryta coating has been first applied over the paper sheet or base and a layer of photographic emulsion has been applied thereover. For obtaining dimensional stability and water-proofing, consideration has been given to the application of a clear polyethylene coating over the baryta layer upon which was coated a layer of photographic emulsion. This polyethylene layer while not interfering with the proper tint of the baryta coating resulted in a major loss in image sharpness in the prints obtained therefrom. Also previous ,baryta coated photographic papers have required ferrotyping by means of a heated pol ished surface to give glossiness as is ordinarily desired in photographic prints.

One object of my invention is to prepare black-andwhite photographic papers having good dimensional, stability, permanent surface characteristics and with a waterproofed base. Another object of my invention is to provide photographic papers which do not require ferrotyping in obtaining glossy prints therefrom. A further object of my invention is to prepare photographic papers having excellent tint and image sharpness. A still further object of my invention is to provide a base for photographic papers of good characteristics. Other objects of my invention will appear herein.

.1 have found that black-and-white photographic papers of good characteristics can be obtained, without the necessity of applying baryta coatings thereto, if the paper base is coated with a layer of polyethylene containing a substantial amount of titanium dioxide prior to applying a layer of the blackand-white photographic emulsion thereon. I have found that papers of even more improved characteristics are obtained by coating the paper with a polyethylene layer containing a substantial amount of titanium dioxide plus a blue, or a mixture of blue and magenta, pigment over the paper prior to. applying the black-andwhite photographic emulsion thereon. I'have found that a further improved black-and-white photographic paper may be obtained if the paper base is coated with a polyv "Ice The paper base employed in accordance with my invention may be any paper which has heretofore been considered useful for photographic paper particularly that having a high alpha-cellulose content. Particularly desirable is paper base to which wet strength has been imparted by the incorporation of wet strength resin. If the photographic emulsion to be applied is not adversely affected by formaldehyde the wet strength resin can be for example, mela mine formaldehyde or urea formaldehyde resin. However, where photographic emulsion adversely affected by formaldehyde is used it is desirable to incorporate a non-aldehydic wet strength resin in the paper, for example cationic thermosetting polyamide epichlorohydrin resin as described in US. Patent 2,926,154, available commercially under the name of Kymene.

The polyolefin employed can be polyethylene or some other polyolefin such as polypropylene or propylene-ethylene copolymer. Although medium density polyolefin has been employed in this connection the use of polyolefins or polyethylenes of high density or low density is not excluded in products in accordance with the invention. The titanium dioxide used preferably is rutile TiO ranging in particle size from 0.1-5 microns such as TiO having average particle size of about 0.23 micron. The amount of titanium dioxide used should be substantial such as Within the range of 3-15 by weight with preference given to the larger amounts of titanium dioxide (such as 10% or more) which can be accommodated in the coating operation used. One convenient means of applying the polyolefin coating to the paper is by means of extrusion coating wherein the melt of the polyolefin-TiO composition is extruded onto the surface of the paper whereupon the coated surface is subjected to pressure by means of a chill roll. Instead of applying the polyolefin coating in this fashion it might be applied by means of a solution thereof in organic solvent followed by driving off the solvent such as by the use of a polished surface at elevated temperature or some other desired means. To assure good adhesion of the polyolefin coating to the paper, it is desirable that the paper he first treated to facilitate adhesiveness such as by electron bombardment or with a primer coat.

In addition to TiO in the polyolefin coating, there may also be present in the compositions blue pigment, or a mixture of blue pigment-and magenta pigment, which further improves the quality of the photographic prints obtained therewith. The amount of tint or colored pigment when used is kept minor ordinarily being no more than 1%, preferably a fraction of 1%. The pigments used should be non-wandering andcompatible with the blackand-white photographic emulsion so as not to affect the sensitivity of'the emulsion and do not Wander from the polyolefin layer either to the emulsion layer or to the paper support. Also these pigments should be light stable and when extrusion coating is used they should exhibit heat stability.

Some pigments which are examples of pigments of this type and which are useful in TiO -polyolefin coatings in accordance with the invention are:

B-LUE PIGMENTS Ultra-Marine Blue EBEX Manufacturer: Ultramarine Chemical Co.

Composition: Percent Silicon dioxide 37-50 Aluminum oxide 2329 Sodium oxide 19-23 Sulfur 8-14 Description:

Vendor No. 59-3805. Pigment Blue 29 Color Index 77007.

3 Shepard Cobalt Blue #3 Manufacturer: Shepard Co.

Composition: Stoichiometric Mixture of Cobalt Oxide and Aluminum Hydrate.

Description: Pigment Blue 28.

Cobalt Aluminated Blue V-3285 Manufacturer: Ferro Colors Corp. Composition: Mixture of Cobalt Oxide and Aluminum Oxide.

MAGENTA PIGMENTS Raspberry V-6260 Manufacturer: Ferro Colors Corp. Composition: Mixture of Cobalt Oxide and Phosphat Oxide.

Hostaperm Pink E-137000 Manufacturer: American-Hoechst Co. Composition: Quinacridone Type Red. Description: Pigment Red-122.

In addition to the pigments listed the polyolefin layer may also if desired contain pigments such as barium sulfate, colloidal SiO calcium carbonate and the like, although including these additional pigments may be dispensed with without adversely affecting the product obtained.

In addition, the polyolefin layer may contain an optical brightener, various of which are available at the present time used preferably in amounts within the range 0.02- 0.50% by weight. Some brighteners which are available for use in polyolefins are described in US. Patent 2,784,- 184 and are marketed by the Geigy Industrial Company under the names Tinopal TCRP, Tinopal SFG, and Tinopal C. A brightener which has been found to be especially useful in polyolefin layers in accordance'with the invention is a commercial material sold under the name Uvitex OB having the following chemical structure:

This material supplied -by Ciba Chemical & Dye Company is described in Belgian Patent 612,775. Other brighteners which have been indicated asbeing useful in photographic products are described in US. Patent 2,639,990 of Kendall et al.

After the paper base has been coated with the layer comprising polyolefin and Ti-O there is applied thereto a layer of a black-and-white photographic emulsion. To obtain good adhesion of the emulsion layer to the paper it is desirable that the paper coated with polyolefin be electron bombarded such as described in British Patent 971,058. In making the paper base to which the emulsion is applied the polyolefin layer is coated over the paper such as at the rate of 4-12 pounds per 1,000 square feet. To give a preferred product the same coverage of clear polyolefin coating may be applied to the reverse side of the paper sheet. In cases Where the polyolefin coating is applied by the extrusion coating method, it has been found desirable to include therein a material which facilitates the coating operation. I have found that if the amide of a fatty acid, saturated or unsaturated, or the like be included in the composition in small amount aids the coating opera tion. If the coating is applied from solution in solvent particularly where the coated layer does not come in contact with some other surface, the coating improver may be dispensed with.

An advantage of the photographic papers and of the paper base useful as a base for photographic papers is that glossy prints may be obtained therewith without the use of ferrotyping. For instance, the use of a highly polished chill roll will give prints having good glossiness without the necessity of applying heat to the print.

The following examples illustrate my invention:

EMMPLE 1 A wet strength paper which had been electron bombarded was coated by extrusion coating with a composition composed of 89.288 parts of medium density polyethylene (Tenite 2908), 0.162 part of Ultramarine Blue EBEX, 0.45 part of Raspberry Violet V-6260, 0.1 part of Armid O (oleylamide) and 10 parts of Du Pont Tipure R- titanium dioxide (rutile form) having an average particle size of 0.1 to 0.35 micron and was treated with a chilled highly polished metal roll. The thus obtained photographic paper base was electron bombarded and was coated with a gelatin-silver halide black-andwhite photographic emulsion. The product, was found, upon exposure and processing, to give photographic prints having good gloss and highly desirable characteristics.

EXAMPLE 2 A wet strength paper which had been electron bombarded was coated by extrusion coating with a composition composed of 89.265 parts of medium density polyethylene (Tenite 2908), 0.1 65 part of Ultramarine Blue EBEX, 0.47 part of Raspberry Violet V6260, 0.1 part of Armid O (oleylamide) and 10 parts of Cabot RF-1 titanium dioxide (rutile form) whose average particle size was within the range of 0.1-0.35 micron and was treated with a chilled, highly polished metal roll. The thus obtained photographic paper base was electron bombarded and was coated with gelatin-silver halide black-and-white photographic emulsion. The product obtained, upon exposure and processing, was found to give photographic prints having good gloss and highly desirable characteristics.

EXAMPLE 3 A wet strength paper which had been electron bombarded was coated by extrusion coating with a composition composed of 89.7349 parts of medium density polyethylene (Tenite 2908), 0.1640 part of Ultramarine Blue EBEX, 0.0011 part of Hostaperm Pink E, 0.10 part of Armid O (oleylamide) and 10 parts of Du Pont R-100 titanium dioxide and was treated with a chilled highly polished metal roll. The thus obtained photographic paper base was electron bombarded and was coated with gelatinsilver halide black-and-white photographic emulsion. The product obtained, upon exposure and processing, was found to give photographic prints having good gloss and highly desirable characteristics.

EXAMPLE 4 A wet strength paper which had been electron bom barded was coated by extrusion coating with a composition composed of 89.1789 parts medium density polyethylene (Tenite 2908), 0.1652 part of Shepard Cobalt Blue #3, 10 parts of Du Pont R-100' titanium dioxide, and 0.7559 part Raspberry Violet V-6260 and was treated with a chilled highly polished metal roll. The thus obtained photographic paper base was electron bombarded and then was coated with gelatin-silver halide black-and-white photographic emulsion. The product obtained, upon exposure and processing, was found to give photographic prints having good gloss and highly desirable characteristics.

EXAMPLE 5 A wet strength paper which had been electron bombarded was coated by extrusion coating with a composition composed of. 89.82985 parts of medium density polyethylene (Tenite 2908), 10 parts of Du Pont R-lOO titanium dioxide, .16520 part of Shepard Cobalt Blue #3, and .00495 part of Hostaperm Pink E and was treated with a chilled highly polished metal roll. The thus obtained photographic paper base was electron bombarded and then was coated with gelatin-silver halide black-and-White photographic emulsion. The product obtained, upon exposure and processing, was found to give photographic prints having good gloss and highly desirable characteristics.

In each of the above Examples 1-5, the paper was coated on the reverse side with a coating of clear polyethylene.

EXAMPLE 6 A wet strength paper which had been electron bombarded was extrusion coated with the following composition:

Percent Medium density polyethylene 89.75 TiO Du Pont R-lOO 10.00 Ultramarine Blue EBEX 0.10 Armid O 0.10 Uvitex OB 0.125

The coating was applied to the paper at the rate of 7.6 lb./ 1000 ft. and was treated with a chilled highly polished metal roll. A clear polyethylene coating was extrusion coated at the rate of 4.5 lb./ 1000 ft. to the wire side of the paper. The pigmented coat was electron bombarded and a layer of a black-and-White gelatino silver halide photographic emulsion was applied thereover. The product was exposed and processed. Photographic prints of good quality were obtained.

EXAMPLE 7 A Wet strength paper which had been electron bombard was extrusion coated with the following composition:

Percent Medium density polyethylene 89.6375 Titanium dioxide, RlOO 10.0000 Ultramarine Blue EBEX 0.1125 Raspberry V-6260 0.0300 Uvitex OB 0.2200

6 T10 because it does not depend on ultra-violet light for its peak excitation, hence, its eifectiveness is not diminished by the presence of TiO The invention has been described in considerable detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinabove, and as defined in the appended claims.

I claim:

1. A photographic element comprising a support which includes a paper base having on and firmly adhered to one surface thereof a layer of polyolefin which contains about 3-15% by weight titanium dioxide and about 0:02- 0.50% by weight optical brightener having a structure represented by the formula:

Ti l

and a light sensitive gelatino silver halide photographic emulsion firmly adhered to said polyolefin layer.

2. The invention according to claim 1 and wherein said polyolefin is polyethylene and on and firmly adhered to the other surface of the paper base is a plastic coat- 3. The invention according to claim 1 and wherein said polyolefin is polyethylene which contains blue pigment in addition to the optical brightener and titanium dioxide, and on and firmly adhered to the other surface of the paper base is a polyethylene coating.

4. The invention according to claim 1 and wherein said polyolefin is polyethylene which contains blue pigment and magenta pigment in addition to the titanium dioxide and optical brightener, and on and firmly adhered to the other surface of the paper base is a polyethylene coating.

References Cited UNITED STATES PATENTS 3,406,070 '10/ 1968 Oetiker et al 9682 NORMAN G. TORCHIN, Primary Examiner J. R. HIGHTOWER, Assistant Examiner US. Cl. X.R. 9667; 117-l55 

